1. Technical Field
The present invention relates to an information processing device.
2. Related Art
A head mounted display (HMD) which is a display mounted on the head is known. The head mounted display generates image light representing an image by using, for example, a liquid crystal display and a light source, and guides the generated image light to user's eyes by using a projection optical system or a light guiding plate, thereby causing the user to visually recognize a virtual image. Of the head mounted display, there are two types including a transmission type in which a user can visually recognize external scenery in addition to a virtual image and a non-transmission type in which the user cannot visually recognize the external scenery. The transmission type head mounted display includes an optical transmission type display and a video transmission type display.
In the transmission type head mounted display, a technique which causes a user to visually recognize a sound as a character image indicating the sound through conversion of the sound is known. For example, JP-A-2011-250100 discloses a technique in which, when content recorded on the recording medium is visually recognized by a user of a head mounted display, sounds included in the content are divided into a person's voice and an environmental sound, a text image indicating the environmental sound is generated, and the generated text image is visually recognized by the user. In addition, JP-A-2010-145878 discloses a technique in which, in chorus practice by a singing chorus and a conductor with a head mounted display conducting the chorus, a chorus member who has a different tempo or pitch of a song is specified, and an image indicating the specified chorus member is visually recognized by the conductor. Further, JP-A-2007-52224 discloses a technique in which, in a head mounted display which allows a user to visually recognize an image, a region where only image light for an alarm such as a warning or a notification is emitted is formed, and thus the image light for the alarm can be easily and reliably visually recognized by a user.
However, in the technique disclosed in JP-A-2011-250100, a user can adjust a method of hearing an external sound different from a sound of content by adjusting the volume of the viewing content through a user's operation. However, there is a case where it is hard to hear the external sound unless the volume of the content is adjusted in a case where the volume of the content is high. In addition, it is desirable to allow an expected external sound which suddenly occurs such as in an emergency to be recognized by a user. Further, in the technique disclosed in JP-A-2010-145878, a sound source in which a tempo or pitch difference of a song occurs can be visually recognized by a user is generated, but the volume of a sound heard by the user cannot be adjusted. Furthermore, in the technique disclosed in JP-A-2007-52224, image light informs a user of a battery level or a signal strength, but, for example, it is desirable to also detect a change in an environment of the user so as to inform the user of the change. Moreover, the above-described problems are not limited to a head mounted display, and are common to a sound output device which outputs sound.